Related Constants Defined Independently

What goes wrong

Two settings that must satisfy a relation (A must stay below B) are written as two independent hard-coded numbers, with nothing deriving one from the other or checking the relation. Editing either one alone silently breaks it.

Example

Connection pool size 50 and the database's connection limit of 40 live in different files; someone raises the pool and connections start failing.

Not to be confused with

Not a stale comment about sizing; the defect is that a coupling once derived (B = 2×A) has become two loose numbers — unlike One Knob Drives Two Budgets, where one setting is wrongly shared by two uses.

Discovered by

@sks24git GitHub

Field notes · 5

@sks24git2026-10-31beat 2 review rounds

A tunable cap was sized as the wait window minus a setup guess, with zero slack, and the test pinned the copied number. Set it at its max and the late run ends after the results are read, its findings silently dropped.

Derive a bound from the clock it must fit. A copied literal stays green when either side moves.
Leave explicit slack for overrun. Clocks overrun; zero margin means routine loss.

@sks24git2026-10-25beat 1 review round

A timeout was set inside the range that the comment one line above estimated for the longest answer. At the slow end the call times out after the answer is generated and billed, and a retry pays again.

Derive a timeout from the limit it guards. Max size at the slowest rate, plus margin.
Pin the relation, not the number. Assert the timeout covers the worst case so no constant edit survives.

@sks24git2026-10-22

A global cap drops below the size of one reserved group while the per-group limits stay put. No group limit can ever bind, so the low-priority group takes every slot and the main work waits.

Scale reserved shares with the cap they split. A share larger than the whole stops reserving anything.
Check every sibling limit when you lower one. They were sized for the old total.

@sks24git2026-09-12beat 1 review round

A job yields the shared queue between file parts, and the part size defaults to the same number as the row cap. Every export is one part, so the yield is dead code at default settings while its doc promises it runs.

Two knobs that must differ cannot differ by accident. Derive one from the other.
A fix unreachable at defaults is a fix on paper. Test the shipped numbers, not the mechanism.

@sks24git2026-09-08

A watcher's lifetime was sized from a doc that said the job takes up to two hours, while the job's real budget was longer. The watch retires before the job ends and nobody hears the result.

Derive a watchdog's cap from the code's own budget, not from prose. Prose rounds down.
A watch that stops must say so. Silence and success look the same.